1 /*
2 * jcomapi.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1994-1997, Thomas G. Lane.0
6 * It was modified by The libjpeg-turbo Project to include only code relevant
7 * to libjpeg-turbo.
8 * For conditions of distribution and use, see the accompanying README file.
9 *
10 * This file contains application interface routines that are used for both
11 * compression and decompression.
12 */
13
14 #define JPEG_INTERNALS
15 #include "jinclude.h"
16 #include "jpeglib.h"
17
18
19 /*
20 * Abort processing of a JPEG compression or decompression operation,
21 * but don't destroy the object itself.
22 *
23 * For this, we merely clean up all the nonpermanent memory pools.
24 * Note that temp files (virtual arrays) are not allowed to belong to
25 * the permanent pool, so we will be able to close all temp files here.
26 * Closing a data source or destination, if necessary, is the application's
27 * responsibility.
28 */
29
30 GLOBAL(void)
jpeg_abort(j_common_ptr cinfo)31 jpeg_abort (j_common_ptr cinfo)
32 {
33 int pool;
34
35 /* Do nothing if called on a not-initialized or destroyed JPEG object. */
36 if (cinfo->mem == NULL)
37 return;
38
39 /* Releasing pools in reverse order might help avoid fragmentation
40 * with some (brain-damaged) malloc libraries.
41 */
42 for (pool = JPOOL_NUMPOOLS-1; pool > JPOOL_PERMANENT; pool--) {
43 (*cinfo->mem->free_pool) (cinfo, pool);
44 }
45
46 /* Reset overall state for possible reuse of object */
47 if (cinfo->is_decompressor) {
48 cinfo->global_state = DSTATE_START;
49 /* Try to keep application from accessing now-deleted marker list.
50 * A bit kludgy to do it here, but this is the most central place.
51 */
52 ((j_decompress_ptr) cinfo)->marker_list = NULL;
53 } else {
54 cinfo->global_state = CSTATE_START;
55 }
56 }
57
58
59 /*
60 * Destruction of a JPEG object.
61 *
62 * Everything gets deallocated except the master jpeg_compress_struct itself
63 * and the error manager struct. Both of these are supplied by the application
64 * and must be freed, if necessary, by the application. (Often they are on
65 * the stack and so don't need to be freed anyway.)
66 * Closing a data source or destination, if necessary, is the application's
67 * responsibility.
68 */
69
70 GLOBAL(void)
jpeg_destroy(j_common_ptr cinfo)71 jpeg_destroy (j_common_ptr cinfo)
72 {
73 /* We need only tell the memory manager to release everything. */
74 /* NB: mem pointer is NULL if memory mgr failed to initialize. */
75 if (cinfo->mem != NULL)
76 (*cinfo->mem->self_destruct) (cinfo);
77 cinfo->mem = NULL; /* be safe if jpeg_destroy is called twice */
78 cinfo->global_state = 0; /* mark it destroyed */
79 }
80
81
82 /*
83 * Convenience routines for allocating quantization and Huffman tables.
84 * (Would jutils.c be a more reasonable place to put these?)
85 */
86
87 GLOBAL(JQUANT_TBL *)
jpeg_alloc_quant_table(j_common_ptr cinfo)88 jpeg_alloc_quant_table (j_common_ptr cinfo)
89 {
90 JQUANT_TBL *tbl;
91
92 tbl = (JQUANT_TBL *)
93 (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, sizeof(JQUANT_TBL));
94 tbl->sent_table = FALSE; /* make sure this is false in any new table */
95 return tbl;
96 }
97
98
99 GLOBAL(JHUFF_TBL *)
jpeg_alloc_huff_table(j_common_ptr cinfo)100 jpeg_alloc_huff_table (j_common_ptr cinfo)
101 {
102 JHUFF_TBL *tbl;
103
104 tbl = (JHUFF_TBL *)
105 (*cinfo->mem->alloc_small) (cinfo, JPOOL_PERMANENT, sizeof(JHUFF_TBL));
106 tbl->sent_table = FALSE; /* make sure this is false in any new table */
107 return tbl;
108 }
109